There is an ongoing and predicted long-term shortage of licensed pharmacists. Due to the increasing age of the population and the ever-increasing number of prescription medicines available, the demand for prescription drugs is growing at a rate that will far exceed the capacity and numbers of licensed pharmacists. The net impact of this imbalance is that pharmacists are increasingly spending more time doing clerical and administrative tasks such as verifying filled prescriptions and checking data entry done by pharmacy technicians. Since the capacity of any one pharmacist is fixed, the output of a pharmacy has become constrained. Consequently, the labor and total cost per prescription continues to rise. The December 2000 Department of Health and Human Services Report to Congress titled “The Pharmacist Workforce: A Study of the Supply and Demand for Pharmacists”, which is hereby incorporated herein by reference, provides an overview of the above problem.
Due to these increased demands on a pharmacist's time, and the resulting increased reliance on technicians and other non-professional staff to fill prescriptions, there is an increased chance for prescription error. While these errors may take many forms, the likelihood of a dangerous or life-threatening “adverse drug event” increases proportionally with the increased chance of prescription fill error. Several studies have shown that prescription error rates are consistently in the 2% to 7% range, with a 4% error rate often cited as a reliable average. The number of deaths due to medication errors is estimated to exceed 7,000 per year in the United States alone. Of course, this number does not include non-fatal conditions from drugs that also result in some form of trauma or injury. The resulting litigation costs associated with these prescription fill errors have also dramatically increased.
Many existing pharmacy filling systems and procedures still require a human operator, whether that operator is a technician or a licensed pharmacist, to validate visually whether the drug that is delivered to the customer is correct. Thus, the human factor can contribute to the majority of prescription fill errors. Existing visual verification techniques rely on comparing an electronic image of the prescribed medication, i.e., a picture of the prescribed medication retrieved from a data library, with the actual medication that is dispensed for the patient. Other systems and procedures rely on comparing the dispensed medication with that in the original manufacturer's supply container, or comparing an electronic image of the filled prescription with an electronic image of the prescribed medication retrieved from a data library.
Each of these verification systems presents similar problems. First, these known verification methods assume that all drugs are visually distinct. This assumption causes many problems because many drugs are not, in fact, visually distinct and, in other cases, the visual differences between drugs is very subtle. For instance, manufacturers are rapidly running out of unique shapes, colors and sizes for their solid dosage form products. To further complicate the problem, generic drug manufactures may be using shapes, colors, and sizes that are different than that of the original manufacturer. Second, even though some known systems may utilize a National Drug Code (NDC) bar code to verify that the supply bottle being accessed corresponds correctly to the patient's prescription, a fraction of filled prescriptions are never picked up and may be returned to the supply shelves for reuse in later prescriptions. Because these reused bottles will not have a manufacturer's bar code on them, it is therefore difficult, if not impossible, to incorporate such validation schemes for these unused prescriptions. Furthermore, in these circumstances, a supply bottle is not available for a visual comparison with the filled prescription. Finally, each of these known manual verification and validation techniques typically requires that the pharmacist spend a significant portion of his day performing these administrative or clerical tasks and allows less time for patient consultation and other professional pharmacist activities.
Solid dosage pharmaceuticals (e.g., pills, tablets, and capsules) each have a unique chemical composition associated with them. This is often referred to as a chemical signature or fingerprint. Pharmaceuticals with varying dosage levels of the same active ingredient may have unique chemical signatures as well. Even slight variations in the active ingredient typically produce a unique chemical signature. In that regard, most pharmaceuticals can be identified accurately by the use of some form of chemical analysis. This same methodology may be applied to other forms of medication (e.g., liquids, creams, and powders). Particularly with solid dosage pharmaceutical products, while a group or package of products may look identical in the visible portion of the spectrum, each product may have a unique chemical signature in the near-infrared wavelength range (800 to 2500 nm). For example, U.S. Pat. No. 6,771,369 to Rzasa et al. describes a pharmaceutical discrimination system that relies on NIR for scanning the contents of a pharmaceutical vial. As another example, U.S. Pat. No. 7,218,395 to Kaye et al. describes the use of Raman spectroscopy for scanning vial contents. As a further example, co-assigned and co-pending U.S. patent application Ser. No. 11/972,849, filed Jan. 11, 2008, discusses a system that scans through the bottom end of the vial as the vial is capped. The disclosures of these patents are hereby incorporated herein in their entireties.
It may be desirable to enhance the reliability and precision of systems that employ spectroscopic verification of pharmaceuticals within vials.